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arXiv 2204.04832cs.DScs.DM
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小度图上时间顶点覆盖的复杂性

The Complexity of Temporal Vertex Cover in Small-Degree Graphs

Thekla Hamm, Nina Klobas, George B. Mertzios, Paul G. Spirakis

AI总结:

本文系统研究了稀疏图上时间顶点覆盖问题(TVC)及滑动窗口变体($Δ$-TVC)的计算复杂性,证明了$Δ$-TVC在路径或环上仍为NP-hard,并为TVC及受限图提出了多项式精确与近似算法。

摘要:

时间图自然地建模了其底层拓扑随时间变化的图。最近,问题 TEMPORAL VERTEX COVER(或 TVC)和 SLIDING-WINDOW TEMPORAL VERTEX COVER(对于固定长度 $Δ$ 的时间窗口,记为 $Δ$-TVC)已被确立为静态图上经典问题 VERTEX COVER 的自然扩展,并与传感器网络中的监控等领域相关联。在本文中,我们启动了对稀疏图上 TVC 和 $Δ$-TVC 复杂性的系统研究。我们的主要结果表明,对于每个 $Δ\geq 2$,即使底层拓扑由路径或环描述,$Δ$-TVC 仍然是 NP-hard。这解决了文献中的一个开放问题,并揭示了 $Δ$-TVC 与 TVC 之间令人惊讶的对比,对于后者,我们在相同设置下提供了一个多项式时间算法。为了规避这种困难性,我们针对底层拓扑由路径给出、在每个时间步具有有界顶点度数、或允许小规模时间顶点覆盖的时间图,提出了多种精确算法和近似算法。

英文摘要:

Temporal graphs naturally model graphs whose underlying topology changes over time. Recently, the problems TEMPORAL VERTEX COVER (or TVC) and SLIDING-WINDOW TEMPORAL VERTEX COVER(or $Δ$-TVC for time-windows of a fixed-length $Δ$) have been established as natural extensions of the classic problem VERTEX COVER on static graphs with connections to areas such as surveillance in sensor networks. In this paper we initiate a systematic study of the complexity of TVC and $Δ$-TVC on sparse graphs. Our main result shows that for every $Δ\geq 2$, $Δ$-TVC is NP-hard even when the underlying topology is described by a path or a cycle. This resolves an open problem from literature and shows a surprising contrast between $Δ$-TVC and TVC for which we provide a polynomial-time algorithm in the same setting. To circumvent this hardness, we present a number of exact and approximation algorithms for temporal graphs whose underlying topologies are given by a path, that have bounded vertex degree in every time step, or that admit a small-sized temporal vertex cover.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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